I'd sign up for Winker. He essentially replaces the ailing back version of Yelich, which we very likely would have received for the remainder of the season.
Rooker could replace the all-star/near-MVP level version of Yelich and would actually add more power to the lineup which we could honestly really use. Controlled for 3 more seasons after this one so the cost would be much higher and there's the question of what to do with him after this season given our existing young OF depth and welcoming back a (hopefully) healthy Yelich.
Personally, I think the Rooker route is worth exploring and opens up some interesting possibilities. For one, they could acquire him with the intention of trading him again in the off-season where he could theoretically net us back quite a bit with his 3 remaining years of control. Also, you could use a Rooker acquisition to set up trading one of a Mitchell/Frelick/Perkins as part of a package for a controllable starter.
Anyways, I wouldn't necessarily limit myself to a rental like Winker.
I do think we need to do something now. This lineup sans Yelich won't hold up in the postseason even if it manages to get us there.